Add support for tracing

[0xTim]

Draft PR to see what things have been added that allowed us to support tracing with Soto.

This will be ongoing as we add more service support and missing pieces

[slashmo]

@adam-fowler Setting span attributes is going to be tricky in Soto.

As you can see in the OpenTelemetry spec there are tons of attributes that are recommended for an AWS SDK not only dependent on the service but also on the exact operation: https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/trace/semantic_conventions/instrumentation/aws-sdk.md. DynamoDB.BatchGetItem e.g. are expected to add an attribute defining all table names (aws.dynamodb.table_names). Granted, these highly specific attributes are not required, though might provide useful insights.

Passing the attributes through Baggage was definitely a last-minute hack and in my opinion, not an ideal solution, as it required us to still make changes to the generated code in the Soto fork: https://github.com/brokenhandsio/soto/commit/6ce0b658944785649c5cced805cab7f0c3bc5c7e

Do you have an idea on how to make this happen while still auto-generating the services? What I thought about roughly would be to have the generated code delegate retrieving span attributes to some object that could be extended for specific use-cases, like DynamoDB batch requests. These extensions would then live alongside the generated code much like the Codable extensions for DynamoDB.

[adam-fowler]

@adam-fowler Setting span attributes is going to be tricky in Soto.

I had a look through the other SDKs to see what they were doing and basically none of the SDKs seem to be have any support for tracing. What they have instead is a separate module that wraps the SDKs and is used to setup spans etc . I'm not sure exactly how it works. I'm going to investigate a little further.

[codecov[bot]]

Codecov Report

Merging #443 (af1dbd3) into main (56f009d) will decrease coverage by 0.10%. The diff coverage is 85.71%.

:exclamation: Current head af1dbd3 differs from pull request most recent head 2d4afc0. Consider uploading reports for the commit 2d4afc0 to get more accurate results

@@            Coverage Diff             @@
##             main     #443      +/-   ##
==========================================
- Coverage   76.41%   76.30%   -0.11%     
==========================================
  Files          65       66       +1     
  Lines        5241     5272      +31     
==========================================
+ Hits         4005     4023      +18     
- Misses       1236     1249      +13     

Impacted Files	Coverage Δ
...urces/SotoCore/Credential/CredentialProvider.swift	97.91% <ø> (ø)
Sources/SotoCore/HTTP/AWSHTTPClient.swift	71.42% <0.00%> (ø)
Sources/SotoCore/Tracing/Baggage+ServiceName.swift	0.00% <0.00%> (ø)
Sources/SotoCore/AWSClient+Paginate.swift	48.80% <50.00%> (ø)
Sources/SotoCore/AWSClient.swift	91.21% <83.60%> (-2.40%)	:arrow_down:
Sources/SotoCore/AWSService.swift	95.65% <100.00%> (ø)
Sources/SotoCore/Credential/ConfigFileLoader.swift	99.28% <100.00%> (ø)
...toCore/Credential/CredentialProviderSelector.swift	100.00% <100.00%> (+6.66%)	:arrow_up:
...toCore/Credential/DeferredCredentialProvider.swift	81.48% <100.00%> (ø)
...toCore/Credential/MetaDataCredentialProvider.swift	95.78% <100.00%> (ø)
... and 12 more

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[adam-fowler]

closing. Solution is available on 7.x.x branch